The ImMaDiab study is a cohort-based investigation with blood sample collection. Both new-onset T1D children and adults will be recruited. Insulin secretion will be stimulated by a standardized meal test. Following T1D diagnosis, blood and urine samples will be collected every 6 months during 30 months in order to measure serum and urine C peptide, glucagon and T-lymphocyte responses against selected beta-cell antigens.